Biaxial Anisotropy

[Vineet Jaiswal]

Hello Sir/Ma'am, 

I want to give the design and simulation parameters in MuMax as in the attached file. Specially I want to know how to give biaxial anisotropy value.

Kindly please give your expert advice on this.

Thanks a lot for your help

Regards,

Vineet Jaiswal

Research Scholar

[Josh Lauzier]

Hello,

By default, mumax has uniaxial and cubic anisotropy terms. If you want to do other types of anisotropy, you need to use a custom field term. An example of this is given on the API page for uniaxial, and it should be pretty easy to extend to biaxial. Here is also an example that was posted, for biaxial specifically.

Cheers,

Josh L.

[Vineet Jaiswal]

Hello Josh,

Thank you very much for your reply, but I am not able to understand the biaxial anisotropy phenomenon in mumax. I want to give a biaxial anisotropy constant value of 50 KJ/m3. Please explain how to give this value. It will be very helpful.

Thank you

[Vineet Jaiswal]

Hello Everyone,

I want to give a biaxial anisotropy constant value of 50 KJ/m3. Please explain how to give this value. It will be very helpful.

I am using this code: 

SetMesh(256, 512, 1, 128e-09/256, 320e-09/512, 0.5e-09, 0, 0, 0)

Msat  = 800e3
Aex   = 13e-12
alpha = 0.25
Kc = 50e3

c1 := Constvector(1,0,0)
c2 := Constvector(0,1,0)
f := Const (-2*Kc/(Msat))
B_c := Mul(f, Madd(Mul( Mul(Mul( Dot(c2, m), Dot(c2, m)),Dot(c1, m)),c1), Mul( Mul(Mul( Dot(c1, m), Dot(c1, m)),Dot(c2, m)),c2), 1,1))
AddFieldTerm(B_c)
AddEdensTerm(Mul(Mul(Const(-0.25),Const(Msat)),Dot(M,B_c)))

There is some error message ;

undefined: Kcrs/GO/src/github.com/mumax/3/cmd/mumax3/main.go:110 script line 6: Kc =50e3

[Josh Lauzier]

Hello,

When defining a variable for the first time, you need to use := instead of just = to initialize it. 'Kc' is not a default mumax variable. You can see this for the other terms like c1,c2 etc, they have := because they are custom terms. Variables like Msat or alpha have already been initialized so they can use just an = . So

Kc := 50e3

should work.

Cheers,

Josh L.